Torque-proportioning differential of the helical gear type are well known in the prior art, as evidenced by the prior patents to Myers U.S. Pat. No. 3,706,239, Dissett U.S. Pat. Nos. 4,625,585, 4,365,524, 4,625,585, 4,677,876, and 4,751,853, among others. Through the use of this type of differential over the years, it has become apparent that the need exists for locking means that are operable either automatically or by the vehicle operator to fully lock the driven axle shafts to each other, for example, upon the occurrence of a spin-out condition of one of the driving wheels. This can be achieved by locking one side gear to the case, or by locking one axle to the case (as is generally done with manual locking systems).
It is also known in the shaft coupling art to provide spiral type one-way clutches including raceway and roller means are arranged in the annular space between a pair of concentrically spaced annular coupling members. Examples of such coupling clutch means are presented by the Kerr U.S. Pat. Nos. 4,341,294 and 5,638,931.
The present invention was developed to provide an improved fully-locking torque-responsive differential that is operated between fully locked and unlocked conditions, respectively, either automatically or by an operator.